The invention relates to the technical sector of the winding of a textile yarn on a holder, generally in the form of a cylindrical mandrel capable of being driven in rotation. The cylindrical mandrel, or holder, can be driven in rotation either via its axis or via one of its generatrices. This winding can be used for spinning, drafting, texturing, torsion, assembling and reeling operations, etc.
It is recalled, as is perfectly well known to a person skilled in the art, that the yarn is dispensed according to a generatrix along the bobbin, in the form of inclined and parallel turns. In general, the displacement speed of the yarn guide is constant. By contrast, it is necessary for the reversal of movement at the ends of the bobbin to be carried out as quickly as possible, in order to prevent the edges of the latter from being thicker than its center.
Many technical solutions have been proposed for the production of what may be referred to as reciprocating systems at very high speed, taking into account the fact that the wound packages must have a perfect density over their entire thickness. Such wound packages may have straight flanks (cylindrical bobbin) or inclined lateral flanks (conical bobbin) or else have a conical generatrix.
According to the teaching of the patent EP 0 235 557, the reciprocating function making it possible to be sure the winding of the yarn bobbin is carried out by means of a double-helix grooved cam for driving a carriage in translational motion parallel to the axis of the bobbin. The carriage drives the yarn before it is wound onto the generatrix forming the bobbin. The reversals in direction of the carriage at the ends of the cam making the reciprocating movement possible make it necessary for the carriage to have a minimal mass in order to limit the resultant forces at the moment of the reversal in direction.
To obtain this minimal mass, the element transmitting the movement between the cam and the carriage generally consists of a shoe, part of which rubs frictionally inside the groove formed in the thickness of the cam.
Such friction is a disadvantage when the yarn tensions and the bobbin speeds are high, since it generates premature wear.
According to the teaching of the patent EP 0 453 622, the reciprocating function is implemented by means of a carriage, the yarn of which is driven by a belt or a cable secured to at least one drive pulley. The change in direction of rotation for carrying out the reciprocating movement of the carriage is executed by the reversal in the direction of the pulley.
Such a solution necessitates sophisticated electronics for executing the reversal in direction, in view of the very short time for executing such reversals and of the accuracy necessary for the positioning of these.
It is also noted that the transmission elements, such as the rotor of the motor, the belt and the pulleys, must undergo reversal in direction, so that it is necessary for their elements to have very low inertia, thus making them fragile when the reeling tensions and speeds are high.